Remove obsolete explanation
Remove obsolete explanation

about passing string to `:if` and `:unless`.
This is a follow up to https://github.com/rails/rails/pull/28058 [ci
skip]

mohitnatoo/rails,aditya-kapoor/rails,baerjam/rails,Envek/rails,EmmaB/rails-1,illacceptanything/illacceptanything,gcourtemanche/rails,assain/rails,betesh/rails,alecspopa/rails,mechanicles/rails,yasslab/railsguides.jp,Sen-Zhang/rails,shioyama/rails,mechanicles/rails,kmcphillips/rails,deraru/rails,kmcphillips/rails,esparta/rails,flanger001/rails,mohitnatoo/rails,repinel/rails,BlakeWilliams/rails,yahonda/rails,shioyama/rails,lcreid/rails,repinel/rails,schuetzm/rails,illacceptanything/illacceptanything,BlakeWilliams/rails,starknx/rails,Edouard-chin/rails,yhirano55/rails,gauravtiwari/rails,yalab/rails,printercu/rails,iainbeeston/rails,MSP-Greg/rails,schuetzm/rails,tjschuck/rails,brchristian/rails,gfvcastro/rails,tjschuck/rails,arunagw/rails,bogdanvlviv/rails,gfvcastro/rails,starknx/rails,untidy-hair/rails,iainbeeston/rails,illacceptanything/illacceptanything,felipecvo/rails,yawboakye/rails,kddeisz/rails,arunagw/rails,illacceptanything/illacceptanything,yalab/rails,utilum/rails,brchristian/rails,bogdanvlviv/rails,utilum/rails,jeremy/rails,joonyou/rails,shioyama/rails,eileencodes/rails,illacceptanything/illacceptanything,jeremy/rails,eileencodes/rails,yawboakye/rails,mohitnatoo/rails,travisofthenorth/rails,assain/rails,vipulnsward/rails,baerjam/rails,kirs/rails-1,joonyou/rails,kmayer/rails,illacceptanything/illacceptanything,esparta/rails,illacceptanything/illacceptanything,baerjam/rails,flanger001/rails,gfvcastro/rails,odedniv/rails,palkan/rails,vipulnsward/rails,yhirano55/rails,Erol/rails,bogdanvlviv/rails,kamipo/rails,Edouard-chin/rails,Edouard-chin/rails,mechanicles/rails,yawboakye/rails,jeremy/rails,vipulnsward/rails,iainbeeston/rails,rafaelfranca/omg-rails,mechanicles/rails,gauravtiwari/rails,pvalena/rails,kddeisz/rails,fabianoleittes/rails,kamipo/rails,MSP-Greg/rails,illacceptanything/illacceptanything,MSP-Greg/rails,kirs/rails-1,BlakeWilliams/rails,kmayer/rails,brchristian/rails,esparta/rails,lcreid/rails,tgxworld/rails,gauravtiwari/rails,Erol/rails,travisofthenorth/rails,prathamesh-sonpatki/rails,yahonda/rails,betesh/rails,shioyama/rails,tjschuck/rails,Sen-Zhang/rails,joonyou/rails,yalab/rails,Erol/rails,odedniv/rails,illacceptanything/illacceptanything,jeremy/rails,yalab/rails,felipecvo/rails,gcourtemanche/rails,MSP-Greg/rails,yawboakye/rails,joonyou/rails,untidy-hair/rails,Sen-Zhang/rails,printercu/rails,kmcphillips/rails,iainbeeston/rails,Stellenticket/rails,tgxworld/rails,mohitnatoo/rails,gfvcastro/rails,betesh/rails,rafaelfranca/omg-rails,Vasfed/rails,tgxworld/rails,untidy-hair/rails,kmcphillips/rails,aditya-kapoor/rails,assain/rails,deraru/rails,arunagw/rails,deraru/rails,Vasfed/rails,gcourtemanche/rails,illacceptanything/illacceptanything,illacceptanything/illacceptanything,Envek/rails,illacceptanything/illacceptanything,yasslab/railsguides.jp,palkan/rails,fabianoleittes/rails,flanger001/rails,pvalena/rails,Envek/rails,arunagw/rails,kirs/rails-1,rafaelfranca/omg-rails,BlakeWilliams/rails,printercu/rails,georgeclaghorn/rails,felipecvo/rails,aditya-kapoor/rails,Vasfed/rails,kddeisz/rails,rails/rails,Vasfed/rails,Edouard-chin/rails,georgeclaghorn/rails,palkan/rails,alecspopa/rails,palkan/rails,lcreid/rails,yasslab/railsguides.jp,rails/rails,pvalena/rails,alecspopa/rails,EmmaB/rails-1,printercu/rails,Erol/rails,utilum/rails,rails/rails,Stellenticket/rails,yhirano55/rails,georgeclaghorn/rails,bogdanvlviv/rails,georgeclaghorn/rails,betesh/rails,yhirano55/rails,starknx/rails,yasslab/railsguides.jp,eileencodes/rails,flanger001/rails,schuetzm/rails,assain/rails,eileencodes/rails,vipulnsward/rails,kamipo/rails,fabianoleittes/rails,aditya-kapoor/rails,notapatch/rails,Envek/rails,prathamesh-sonpatki/rails,prathamesh-sonpatki/rails,rails/rails,notapatch/rails,odedniv/rails,yahonda/rails,Stellenticket/rails,tjschuck/rails,untidy-hair/rails,esparta/rails,utilum/rails,deraru/rails,repinel/rails,tgxworld/rails,kmayer/rails,illacceptanything/illacceptanything,yahonda/rails,illacceptanything/illacceptanything,travisofthenorth/rails,Stellenticket/rails,fabianoleittes/rails,illacceptanything/illacceptanything,repinel/rails,baerjam/rails,prathamesh-sonpatki/rails,pvalena/rails,EmmaB/rails-1,kddeisz/rails,schuetzm/rails,notapatch/rails,notapatch/rails,travisofthenorth/rails,lcreid/rails